Chronograph



T. K. RIGGEN CHRONOGRAPH April 1, 1941.

Filed Oct. 28, 1939 2 Sheets-Sheet 1 o I. I y

j I INYENTOR.

T. K. RIGGEN CHRONOGRAPH April 1, 1941.

Filed Oct. 28, 1959 2 Sheets-Sheet 2 Patented Apr. 1, 1941 CHRONOGRAPH Theodore K. Riggen, Elmira, N. Y., assignor to Bendix Aviation Corporation, South Bend, Ind., a corporation of Delaware Application October 28, 1939, Serial No. 301,859

9 Claims.

The present invention relates to a chronograph.

for fuse timing mechanism, and more particularly to a device for recording graphically the timing of fuse mechanism for projectiles.

In testing the timing mechanism of fuses, it is customary to rotate the fuse about its axis at approximately its.average speed during flight, and to continuously record the vibration frequency of the pallet of the escapement mechanism by photoelectrically' controlled chronographic apparatus. The record so obtained provides a close check on the setting of the escapement mechanism, but the chronograph does not furnish any information with respect to the operation of the other structural components of the fuse, nor does it record the time elapsed between the initiation of rotation of the fuse and the actuation of the firing pin, the control of which elapsed time is, of course, the primary function of the fuse.

It is an object of the present invention to provide a novel device for recording the time interval between initiation of the spinning of a time fuse for projectiles and the actuation of the firing pin of the projectile.

It is another object to provide such a device which is effective andreliable in operation while being simple and economical in construction.

It is a further object to provide such a chronographic device in which the firing pin of the projectile is arranged to cause operation of the device to record the time of actuation thereof. It is another object to provide such a device which, while providing a continuous record of the operation of the timing mechanism, is arranged to also record the elapsed time between the starting of the timing mechanism and the actuation of the firing pin. v

It is another object to provide such a device which requires no alteration in the mechanism of the chronograph to enable it to'perform both said functions.

It is another object to provide such a device which incorporates an attachment to the fuse structure readily applied to and removed therefrom, for causing the chronograph to record the' connection with the accompanying drawings in which:

Fig. 1 is a semi-diagrammatic illustration of a photoelectric recording device of the type employed in carrying out the present invention;

Fig. 2 is a reproduction on an enlarged scale of a sample record such as obtained from such photoelectric apparatus; 7

Fig. 3 is a top plan view of a fuse timing structure to which a preferred embodiment of the invention has been applied, the parts being shown in the normal or non-fired position;

Fig. 4 is a similar view showing the parts in the positions assumed after the firing pin has been actuated;

Fig. 5 is a side elevation of the structure shown in Fig. 3;

Fig. 6 is a side elevation of a fuse timing mechanism of the type employed in the present invention, parts being broken away for the sake of clarity;

Fig. '7 is a top plan view of the structure illustrated in Fig. 6;

Fig. 8 is a detail in perspective of the anchoring In Figs. 3 to 7 inclusive there is illustrated a conventional form of fuse timing mechanism including a cylindrical body I built up from laminations or plates which are stacked and maintained in unified relation by any suitable means and which houses a clockwork mechanism including a vibrating pallet 2, a portion of which is visible through an opening 3 in the end plate 4 of the fuse as shown in Fig. 3. The fuse further comprises a firing pin 5 (Fig. 4) which when actuated is projected up through the end plate '4 of the fuse in order to strike a percussion cap properly located in the path of the firing pin when the fuse is assembled in the nose of the projectile.

Inasmuch as thetiming of the fuse to actuate the firing pin is controlled by the vibration of the pallet 2, calibration of the fuse may best be effected by recording the, frequency of vibration of the pallet. Since, however, the operation of the pallet may be affected by the accelerational and centrifugal forces engendered by the discharge and flight of the projectile, it is desirable to observe and record the vibrations of the pallet when the fuse and contained timing mechanism are subjected to conditions approximating those in service.

' function is illustrated semi-diagrammatically in Fig. 1. As there shown, a motor is arranged to rotate a chuck which holds a fuse to be tested. The motor may be directly connected or may rotate the chuck througha suitable transmission as shown. In either case, the arrangement is such as to rotate the fuse at approximately the averagespeed of rotation obtaining during fiight.

A source of light 6 is arranged above the fuse as positioned in the chuck and is provided with a condensing lens 1 of any preferred type which is arranged to focus the beam of light from the light source approximately at the center of a mirror 8. The mirror is provided wi-tha central opening or unsilvered portion 9 permitting passage of the light beam whch, diverging therefrom, impinges on a second condensing lens ll, Lens I l brings the beam back into approximately a parallel bundle of rays which brightly illuminate the end of the fuse over an area sufficient to at all times include the observation opening 3.

The lens ii is arranged to cooperate with the mirror 8 in projecting an image of the fuse so illuminated on the sensitive element of a photoelectric cell indicated diagrammatic-ally at l2.

thermionic tube amplifier, and are then conducted through a filter network which is arranged to pass only electrical oscillations of approximately the frequency of vibration of the pallet 2. The output from the filter, amplified again if necessary, is used to operate a printing device which records on a moving tape marks corresponding to a fixed submultiple of the electrical oscillations received thereby. The printer thus makes a mark on the tape every time the pallet 2 of the fuse makes a certain fixed number of vibrations as observed through the opening 3 by the photoelectric cell, and this observation of the motion of the pallet across said opening is entirely unaffected by the rotation of the fuse by the motor to simulate conditions of flight.

Since the printing device is arranged to feed the tape past the printing bar at a constant speed, the distances between the marks on the tape form an accurate time measurement. The tape so printed thus constitutes a continuous record of the rate of vibration of the pallet during the entire actuation of the timing mechanism of the fuse.

The printing device is arranged to automatically start the tape as soon as electrical oscillations are received from the amplifier, and to stop the tape as soon as such electrical oscillations cease.

According to the present invention, means are provided for utilizing this chronographic apparatus to record on the tape the time of actuation of the firing pin so as to automatically check the operation of the firing pin actuating means and at the same time check the setting of the fuse in respect to the time interval between starting the fuse and actuation of the firing pin. As shown in Figs. 3, 4, 5 and 8 to 10 inclusive, these functions are accomplished by mounting on the fuse a shutter mechanism which is controlled by the actuation of the firing pin to obscure the observation opening 3 the instant that the firing pin is actuated For this purpose an anchor plate I3 is arranged to be movably clamped on the end of the fuse by means of a screw it; preferably having. a knurled head as indicated at l5 for facilitating removal.

Means for locating the anchor plate on the fuse is provided in the form of a stud l6 riveted to the anchor plate and arranged to project into an opening l'l formed in the end plate 4 of the fuse.

A shutter I 8 is pivoted on the screw l4 and yield-ably .pressed against the anchor plate as by means of a spring i9. Studs 2| and 22 fixedly mounted in the shutter I8 project beneath said shutter so as to engage the edge of the anchor plate l3. The edge of the anchor plate is of such conformation, and the studs 2| and 22 are so located, that the shutter is normally held away from the observation opening 3 as shown in Fig. 3. Clockwise rotation of the shutter from such position is prevented by stud 22, and counterclockwise rotation is prevented by stud 2|. In this position it will be noted that the shutter covers the end of the firing pin 5 so that when the firing pin is actuated and thereby projected upwardly through the top of the fuse, it impinges on the underside of the shutter and raises it sufiiciently to free the stud 2| from its engagement with the anchor plate I3. The shutter is thereby free to move by centrifugal force to the position illustrated in Fig. 4 Where the observation opening 3 is covered thereby.

One well-known method of controlling the actuation of the firing pin from the timing mechanism is illustrated in Figs. 6 and 7. As there shown, a timing disc 24 is arranged to be rotated slowly by the timing mechanism so as to bring a notch 25 in the periphery thereof into registry with 2. lug 26 formed on a pivoted latch member 27. Latch member 21 is provided with a weight 28 which is arranged to move out by centrifugal force when the opening 25 in the timing disc registers with said lug 26; The consequent rotation of the latch member is used .to secure actuation of the firing p'm.

When it is desired to set the timing mechanism of the fuse, the timing disc 24 is rotated to move the opening 25 a predetermined angular distance from the lug.26, depending upon the time interval desired between the starting of the timing mechanism and the actuation of the firing In the operation of this embodiment of the invention, the fuse is set to actuate the firing pin after a predetermined time interval in the usual manner. The anchor plate and shutter, which are preferably maintained assembled on the screw l4 in any suitable manner as by the formation of shoulders 23 on the screw I4, are mounted on the fuse and the fuse inserted in the chuck of the chronograph. When the motor is ener-' gized to spin the fuse, operation of the timing mechanism of the fuse 'is instituted and the printer is actuated by the oscillations received from the amplifier to record the vibrations of the pallet as above described.

When the firing pin 5 is released by the timing mechanism, it is projected into engagement with the shutter l8, raising the stud 2| out of engagement with the anchor plate l3 whereby the shutter rotates by centrifugal force on its pivot screw l4 into the position illustrated in Fig. 4 where the observation opening 3 is covered. Electrical oscillations derived from the vibration of the pallet thereupon cease, and the printing mechanism immediately stops, thus recording the time of actuation of the firing pin. The total length of tape, therefore, from the first to the last mark thereon is a measure of the elapsed time between the starting of the timing mechanism and the actuation of the firing pin, thus providing a check on the setting of the fuse and on the operation of the firing mechanism.

Although but one embodiment of the invention has been shown and described in. detail, it will be understood that other embodiments are possible and various changes may be made in the design and arrangement of the parts without departing from the spirit of the invention as defined in the claims appended hereto.

What is claimed is:

1. In combination, a mechanical time fuse hav ing a casing, an escapement mechanism mounted therein including a vibrating pallet, and a firing pin controlled by the escapement, said casing having an opening permitting observation of the pallet; a shutter pivotally mounted on the casing adjacent said opening, and a detent normally holding said shutter clear of the opening, said firing pin being arranged when actuated to enage the shutter and release it from the detent.

2. In combination, a mechanical time fuse having a casing, an scapement mechanism mounted therein including a vibrating pallet, and a firing pin controlled by the escapement, said casing having an opening permitting observation of the pallet; an anchor member adapted to be detachably fixed on the casing, and a centrifugally actuated shutter pivoted on the anchor member and normally held thereby in a position adjacent to, but clear of, said opening, said firing pin being arranged when actuated to engage the shutter and release it from the anchor member whereby the shutter is free to move over and cover the opening,

3. In a device of the class described, a fuse structure having a vibrating pallet, an opening for observing the pallet, and a firing pin; means for rotating the fuse structure, a shutter pivoted to the fuse adjacent said opening and movable by centrifugal force to cover the opening, and latch means normally holding the shutter in open position, said shutter being so arranged that actuation of the firing pin releases the shutter from the latch and allows the shutter to cover the opening.

4. In a device of the class described, a fuse structure having a vibrating pallet, an opening Cir for observing the pallet, and a firing pin; means for rotating the fuse structure, means forming a graphic record of the frequency of vibration of the pallet as observed through the opening, and means including centrifugal means under the control of the firing pin for showing on said record the time of actuation of the firing. pin.

5. In a testing device for fuses containing a clockwork and a firing pin, means for making a graphic record of the operation *of the clockwork, and means for showing on said record the time of actuation of the firing pin.

6. In a testing device for fuses containing a clockwork and a firing pin, means for making a graphic record of the operation of the clockwork, and means controlled by actuation of the firing pin for interrupting said record.

7. In a testing device for fuses containing a clockwork and a firing pin, means for making a graphic record of the operation of the clockwork including means for starting the record respon sive to the starting of the clockwork, and means controlled by the actuation of the firing pin cooperating with the starting means to stop the record.

8. In combination with a fuse having a clockwork escapement mechanism and a firing pin controlled thereby, testing mechanism therefor including means for observing the escapement mechanism, means controlled by the observing means for making a continuous chronographic record of the operation of the escapement mechanism, and means controlled by the firing pin for obscuring the escapement mechanism from the observing means.

9. In combination with a fuse having a clock work escapement mechanism and a firing pin controlled thereby, testing mechanism therefor including means for rotating the fuse at approximately its speed in flight and for simultaneously observing the operation of the escapement mechanism, means controlled by the observing means for making a continuous chronographic record of the operation of the escapement mechanism, and means rendered effective by the actuation of the firing pin for covering the escapement mechanism.

THEODORE K. RIGGEN. 

